An approach to optimal sensor placement for vibration tests on large structures

The critical issue of vibration test on hull structures with large size is the numerous amounts of sensors. Too many sensors lead to excessive consumption whereas notable error would come from reducing the number of sensors. An approach is proposed to reconstruct the complete structural vibration via much fewer sensors. This iterative progress eliminates the sensor location that contributes the most signif icantly to the condition number of modal matrix in each cycle. Along with the iteration, the condition number goes down quickly to a certain level, but rises suddenly after lots of calculating cycles. The optimal number of sensors is the one before the condition number zooming. The corresponding sensor locations are also optimal. An experiment on cylindrical shell demonstrates that vibration responses reconstructed from the data of 26 optimal sensors are consistent with the responses measured by 200 initial sensors. The vibration error is only 2.4 dB. This approach may be applied to vibration test and measurement on large structures.